did the film run out and you tried to change it? If so I have great news for you the machine isnt broke:)
The 4250 is a unique design. the red rubber rollers arent driven. only the back pull rollers are, the grey ones.
So take a file folder, or threading card. Wrap both rolls of new film around it, and put in red rollers then turn them by hand till the film reaches they grey rollers in the back, then turn on machine and your all set.
another thing on some 4250s the interlock switch on the feed tray will stop the machine from running. its a pin device attached to tray that engages a switch in the frame near the front left adjacent to a side cover screw.
GBC had 3 variations of that interlock switch.
1 not used at all, the best and never causes trouble:)
2 prevents drive from running if not engaged
3 machine wouldnt power on at all unless engaged
I have seen all 3 versions in the field. I fix these machines for a living in pittsburgh PA.
please let me know if this advice helped, bob
bob haller service and sales pittsburgh pa 412 366 4906, July 2011